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