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