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