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