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)(11,21)(12,17)(13,18)(14,19)(15,20)(16,24)(22,23)(25,26)(27,33)(28,32)(29,31)(30,34)(35,39)(36,38)(37,40) involution — undirected(1,3,5,7)(2,4,8,6)(9,11)(10,16)(12,22)(13,19)(14,23)(15,24)(17,18)(20,21)(25,27,30,29)(26,31,34,33)(28,36,37,35)(32,39,40,38)(1,3)(2,6)(4,8)(5,7)(25,26,30,34)(27,31,29,33)(28,32,37,40)(35,38,36,39)(1,2,5,8)(3,4,7,6)(9,12,15,19)(10,17,20,14)(11,22,24,13)(16,18,21,23)(25,26)(27,31)(28,32)(29,33)(30,34)(35,38)(36,39)(37,40)(1,3)(2,4)(5,7)(6,8)(9,13,15,22)(10,18,20,23)(11,19,24,12)(14,16,17,21)(25,28,30,37)(26,32,34,40)(27,35,29,36)(31,38,33,39)(1,4)(2,7)(3,8)(5,6)(9,14,15,17)(10,19,20,12)(11,23,24,18)(13,21,22,16)(25,29,30,27)(26,33,34,31)(28,35,37,36)(32,38,40,39)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.