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