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