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