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