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