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