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