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