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