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