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