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