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