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