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