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