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