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