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