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