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