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