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