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