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