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)(11,21)(12,25,28,33)(13,18)(14,19)(15,20)(16,23)(17,27,34,26)(22,36,38,30)(24,31)(29,32)(35,37,40,39)(1,3,5,2)(4,7,6,8)(9,11,13,23,15,24,14,29)(10,16,19,21,20,32,18,31)(12,22,27,39,28,38,26,37)(17,30,33,35,34,36,25,40)(4,6)(7,8)(9,12)(10,17)(11,22)(13,27)(14,26)(15,28)(16,30)(18,25)(19,33)(20,34)(21,35)(23,39)(24,38)(29,37)(31,40)(32,36) involution — undirected(9,13,15,14)(10,18,20,19)(11,23,24,29)(12,26,28,27)(16,31,32,21)(17,33,34,25)(22,37,38,39)(30,35,36,40)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.