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