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