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