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