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