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