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