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