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