One vertex per element, one color per generator, with an edge from x to x·s.
(9,10)(11,13)(12,20)(14,15)(16,18)(17,22)(19,23)(21,24)(25,26)(27,36)(28,33)(29,39)(30,34)(31,35)(32,38)(37,40) involution — undirected(1,2)(3,8)(4,6)(5,7)(10,15)(11,18)(17,20)(19,24)(25,27)(26,32)(28,30)(29,37)(31,38)(33,40)(34,39)(35,36) involution — undirected(1,3,5,6)(2,4,7,8)(9,11)(10,16)(12,19)(13,15)(14,18)(17,23)(20,21)(22,24)(25,28,31,29)(26,33,35,39)(27,30,38,37)(32,40,36,34)(1,2)(3,4)(5,7)(6,8)(9,11)(10,16)(12,19)(13,15)(14,18)(17,23)(20,21)(22,24)(25,29,31,28)(26,33,35,39)(27,37,38,30)(32,40,36,34)(1,2)(3,4)(5,7)(6,8)(9,12,14,22)(10,17,15,20)(11,19,18,24)(13,21,16,23)(25,30,31,37)(26,34,35,40)(27,28,38,29)(32,39,36,33)(1,4)(2,6)(3,7)(5,8)(9,13,14,16)(10,11,15,18)(12,21,22,23)(17,19,20,24)(25,26)(27,32)(28,33)(29,39)(30,40)(31,35)(34,37)(36,38)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.