One vertex per element, one color per generator, with an edge from x to x·s.
(9,10)(11,14)(12,17)(13,16)(15,20)(18,21)(19,23)(22,24)(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)(10,11)(15,17)(16,18)(22,23)(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)(9,10,14,11)(12,15,20,17)(13,16,21,18)(19,22,24,23)(25,28,31,29)(26,33,35,39)(27,30,38,37)(32,40,36,34)(1,2)(3,4)(5,7)(6,8)(9,11,14,10)(12,17,20,15)(13,18,21,16)(19,23,24,22)(25,29,31,28)(26,33,35,39)(27,37,38,30)(32,40,36,34)(1,2)(3,4)(5,7)(6,8)(9,12,14,20)(10,15,11,17)(13,19,21,24)(16,22,18,23)(25,30,31,37)(26,34,35,40)(27,28,38,29)(32,39,36,33)(1,4)(2,6)(3,7)(5,8)(9,13,14,21)(10,16,11,18)(12,19,20,24)(15,22,17,23)(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.