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