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