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